I get this loud clicking noise coming from under my hood and i have no idea what it is. It sounds like the motor, but the car runs normally, in and out of boost. The oil pressure is normal and no CEL's or any other warning signs are going off. The idle is normal and in about mid RPM range the noise is the loudest. The only thing out of the ordinary that i can find is that there is smoke coming from the pcv breather. I am perplexed, any help, suggestions, things to check for? BTW, i'm gonna do a compression test early next week. Thanks.